Abstract Graphene oxide (GO) is an attractive candidate for use as a nano-reinforcement in cement composites. However, a prerequisite for GO to fulfill its function is the uniform dispersion of GO throughout the cement matrix. In this paper, the dispersion behavior of GO modified by lignosulfonate (LS), polycondensate of β-naphthalene sulfonate formaldehyde (PNS), and polycarboxylate superplasticizer (PC) in cement pore solution was investigated by a combination of visual observation, optical microscopy and transmission electron microscopy (TEM). Results show that GO modified by PC exhibited better dispersion in cement pore solution than LS and PNS. Zeta potential analysis demonstrated that LS and PNS failed to adsorb onto the GO surface when pH > 11, while successful attachment of PC to GO was achieved even in the alkaline environment. The dispersion mechanisms of PC modified GO were thought to be a combination of covering the surface of GO, lowering the free Ca2+ concentration and impeding the cross-linking of Ca2+ due to steric hindrance effect of PC. With the addition of PC modified GO, the fluidity and mechanical strength of cement composites were improved significantly, indicating that this dispersion route can be successfully used for the preparation of GO reinforced cement composites.

中文翻译：

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不同减水剂改性GO在水泥孔隙溶液中的分散行为研究

摘要 氧化石墨烯 (GO) 是一种有吸引力的候选材料，可用作水泥复合材料中的纳米增强材料。然而，GO 实现其功能的先决条件是 GO 在整个水泥基体中的均匀分散。本文采用目视、光学显微镜和透射相结合的方法研究了木质素磺酸盐（LS）、β-萘磺酸甲醛缩聚物（PNS）和聚羧酸减水剂（PC）改性的GO在水泥孔隙溶液中的分散行为。电子显微镜（TEM）。结果表明，PC改性的GO在水泥孔隙溶液中的分散性优于LS和PNS。Zeta 电位分析表明，当 pH > 11 时，LS 和 PNS 无法吸附到 GO 表面，而即使在碱性环境中也能成功地将 PC 连接到 GO。PC 改性 GO 的分散机制被认为是覆盖 GO 表面、降低游离 Ca2+ 浓度和由于 PC 的位阻效应阻碍 Ca2+ 交联的组合。PC改性GO的加入显着提高了水泥复合材料的流动性和机械强度，表明该分散途径可成功用于制备GO增强水泥复合材料。